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稳定同位素技术已成为摄食生态学研究的有力手段之一,动物不同组织的稳定同位素周转速率和分馏系数可用于分析其不同生活史时期的摄食状况,进而解释其洄游行为。以黄颡鱼(Pelteobagrus fulvidraco)为研究对象,通过改变黄颡鱼饵料模拟食性转换过程,研究黄颡鱼不同组织碳、氮稳定同位素周转速率和分馏系数,探讨组织生长及新陈代谢作用对各组织稳定同位素周转的相对贡献比例。结果表明,黄颡鱼各组织碳、氮稳定同位素半衰期分别为28.0 d和35.7 d(粘液),25.8 d和63.6 d(肝脏),106.5 d和64.2 d(鱼鳍),196.9 d和196.8 d(鳃),肌肉的碳稳定同位素半衰期为92.6 d,其粘液、肝脏周转速率较快,鱼鳍、肌肉和鳃较慢。黄颡鱼不同组织碳、氮稳定同位素分馏系数(Δδ13C和Δδ15N)范围分别为-2.1‰~2.0‰和-1.4‰~2.4‰。研究认为,除鳃以外,黄颡鱼其他组织的稳定同位素周转均以代谢作用占主导(>60%),生长作用贡献比例较小。黄颡鱼的粘液和肝脏可反映短期内的摄食转换,而鱼鳍、肌肉和鳃则反映较长时间尺度的摄食特征。
Stable isotope techniques have become one of the powerful tools in the research of feeding ecology. Stable isotope turnover rates and fractionation coefficients in different tissues of animals can be used to analyze the feeding status in different life stages and then explain their migratory behavior. In this paper, Pelteobagrus fulvidraco was used as the research object to study the change of carbon and nitrogen stable isotope turnover rates and fractionation coefficients of different tissues of Catfish by simulating the process of food conversion. The effects of tissue growth and metabolism on the stability of each tissue were studied The relative contribution of isotope turnover ratio. The results showed that the half-lives of stable isotopes of carbon and nitrogen in each tissue were 28.0 d and 35.7 d (mucus), 25.8 d and 63.6 d (liver), 106.5 d and 64.2 d (fins), 196.9 d and 196.8 d Gill), muscle carbon stable isotope half-life of 92.6 d, the mucus, liver turnover rate faster, the fins, muscles and gills slower. The carbon and nitrogen stable isotope fractionation coefficients (Δδ13C and Δδ15N) of different tissues of the catfish were ranged from -2.1 ‰ to 2.0 ‰ and -1.4 ‰ to 2.4 ‰, respectively. Studies suggest that, except for the gills, the stable isotope turnover of other tissues of the catfish is dominated by metabolism (> 60%), the contribution of growth to a lesser extent. Catfish mucus and liver may reflect the short-term food conversion, while the fins, muscles and gills are reflected on the longer time scale feeding characteristics.